Since they're his dogs I don't want to interfere with his methods, although I consider them wrong. My problem is that I want to get a dog of my own, but to show him that I'm the pack leader. I'm worried that it would be too confusing for my (the youngest) dog if older dogs are allowed on the couch/bed and he isn't, older dogs can pull the leash while on the walk, while he needs to walk beside or behind me, other two can go through the door and get attention first while he needs to wait to go through or get petted.
Answer:
In order for a dog to totally respect and obey humans, the humans around her need to be consistent. If you bring a dog into a home where one person does not display leadership you are not going to accomplish that leadership with the third dog. Especially if there are two other dogs in the home that are allowed to act in dominant or disrespectful manners. When humans and dogs live together they become one pack. If half the pack is not balanced the rest of the pack cannot be balanced.
In order for a dog to totally respect and obey humans, the humans around her need to be consistent. If you bring a dog into a home where one person does not display leadership you are not going to accomplish that leadership with the third dog. Especially if there are two other dogs in the home that are allowed to act in dominant or disrespectful manners. When humans and dogs live together they become one pack. If half the pack is not balanced the rest of the pack cannot be balanced.